Code
  1//说明：本程序有一定代码冗余，若分割为多个函数的形式会使程序简洁明了。
  2#include <iostream>
  3using namespace std;
  4#include <queue>
  5#include <stack>
  6
  7const int N=5;        //物品个数，其中包括（0,0）.
  8const float W=60;    //背包最大载重。
  9struct GoodsStruct
 10{
 11    int ID;        //物品编号
 12    float benefit;    //物品效益
 13    float weight;    //物品重量
 14    int com;    //标记最优解中是否含有该物品，有则为1,没有则为0.
 15};
 16
 17int main()
 18{
 19    GoodsStruct StructGoods;
 20    GoodsStruct StructTemp;
 21    GoodsStruct StructCom;
 22    GoodsStruct StructCalTemp;
 23    queue <GoodsStruct> QueueGoods;    //存放原始物品信息的队列，用于求解集合，完后全部被弹出。
 24    queue <GoodsStruct> QueueSourse;//存放原始物品信息的队列，用于回溯过程，作为最后结果。
 25    queue <GoodsStruct> QueueTemp;    
 26    queue <GoodsStruct> QueuePush;
 27    queue <GoodsStruct> QueueCom;    //两个队列在支配规则下的合并结果队列。
 28    queue <GoodsStruct> QueueComTemp;//两个队列在支配规则下的合并时的临时变量。
 29    queue <GoodsStruct> QueueCalTemp;
 30    stack <queue<GoodsStruct>> StackGoods;
 31
 32    /**//*float benefits[N]={0,2,2,1};//测试数据。
 33    float weights[N]={0,2,3,2};*/    
 34    /**//*float benefits[N]={0,2,3,4};
 35    float weights[N]={0,1,2,5};*/    
 36    float benefits[N]={0,2,5,8,1};
 37    float weights[N]={0,10,15,6,9};    
 38    bool check=false;
 39
 40    //将物品信息存入队列和堆栈中。
 41    for (int i=0;i<N;i++)
 42    {
 43        StructTemp.ID=i;
 44        StructTemp.benefit=benefits[i];
 45        StructTemp.weight=weights[i];    
 46        StructTemp.com=0;
 47        QueueSourse.push(StructTemp);
 48    }
 49
 50    /**///
 51    //求解集合
 52    //(0,0)先入栈。
 53    QueueGoods=QueueSourse;
 54    StructGoods=QueueGoods.front();
 55    QueueGoods.pop();
 56    QueuePush.push(StructGoods);
 57    StackGoods.push(QueuePush);
 58
 59    while (!QueueGoods.empty())
 60    {    
 61        StructGoods=QueueGoods.front();
 62        QueueGoods.pop();
 63        QueueTemp=QueuePush;
 64        //计算出临时队列的过程，此处使用支配规则。
 65        while (!QueueTemp.empty())
 66        {
 67            StructTemp=QueueTemp.front();
 68            QueueTemp.pop();
 69            StructTemp.benefit+=StructGoods.benefit;
 70            StructTemp.weight+=StructGoods.weight;
 71
 72            QueueCalTemp=QueuePush;
 73            if (StructTemp.weight<=W)
 74            {                
 75                while (!QueueCalTemp.empty())
 76                {
 77                    StructCalTemp=QueueCalTemp.front();
 78                    QueueCalTemp.pop();
 79                    if (StructTemp.weight>=StructCalTemp.weight && StructTemp.benefit<StructCalTemp.benefit)
 80                    {
 81                        //支配规则把新值StructCom去掉。
 82                        check=false;
 83                        break;
 84                    }                 
 85                    else
 86                    {
 87                        check=true;
 88                    }
 89                }
 90                if (check==true)
 91                {
 92                    QueueComTemp.push(StructTemp);
 93                }                
 94            }            
 95        }
 96
 97        //QueueComTemp与QueuePush通过支配规则进行合并，去掉不可能的解。
 98        while (!QueuePush.empty())
 99        {
100            StructCom=QueuePush.front();
101            QueuePush.pop();
102            QueueTemp=QueueComTemp;
103            while (!QueueTemp.empty())
104            {
105                StructTemp=QueueTemp.front();
106                QueueTemp.pop();
107                if (StructCom.weight>=StructTemp.weight && StructCom.benefit<StructTemp.benefit)
108                {
109                    //支配规则把新值StructCom去掉。
110                    check=false;
111                    break;
112                }                 
113                else
114                {
115                    check=true;
116                }
117            }
118            if (check==true)
119            {
120                QueueCom.push(StructCom);
121            }            
122        }
123        //将QueueComTemp全部接入QueueCom中，因为QueueComTemp不会被支配掉。
124        while (!QueueComTemp.empty())
125        {
126            StructTemp=QueueComTemp.front();
127            QueueComTemp.pop();
128            QueueCom.push(StructTemp);
129        }
130        StackGoods.push(QueueCom);
131        QueuePush=QueueCom;
132        while (!QueueCom.empty())
133        {
134            QueueCom.pop();
135        }
136    }
137
138    /**///
139    //求解最终序偶
140    QueueTemp=StackGoods.top();    
141    StructGoods=QueueTemp.back();
142    while (!QueueTemp.empty())
143    {
144        StructTemp=QueueTemp.front();
145        QueueTemp.pop();
146        if (StructGoods.weight<StructTemp.weight)
147        {
148            StructGoods=StructTemp;
149        }
150    }    
151    cout<<"(P,W)=("<<StructGoods.benefit<<","<<StructGoods.weight<<")"<<endl;
152
153    /**///
154    //回溯        
155    int count=N-1;
156    StackGoods.pop();
157    while(!StackGoods.empty())
158    {
159        QueueTemp=StackGoods.top();
160        StackGoods.pop();
161        while (!QueueTemp.empty())
162        {
163            StructTemp=QueueTemp.front();
164            QueueTemp.pop();            
165            if (StructTemp.benefit==StructGoods.benefit && StructTemp.weight==StructGoods.weight)
166            {        
167                check=false;
168                for (int i=0;i<N;i++)
169                {
170                    StructCalTemp=QueueSourse.front();
171                    QueueSourse.pop();
172                    if (StructCalTemp.ID==count)
173                    {
174                        StructCalTemp.com=0;                        
175                    }
176                    QueueSourse.push(StructCalTemp);
177                }
178                break;
179            } 
180            else
181            {
182                check=true;
183            }            
184        }
185        if (check==true)
186        {
187            for (int i=0;i<N;i++)
188            {
189                StructCalTemp=QueueSourse.front();
190                QueueSourse.pop();
191                if (StructCalTemp.ID==count)
192                {
193                    StructCalTemp.com=1;                        
194                }
195                QueueSourse.push(StructCalTemp);
196            }    
197            StructGoods.benefit-=StructCalTemp.benefit;
198            StructGoods.weight-=StructCalTemp.weight;
199        }        
200        count--;
201    }
202
203    QueueSourse.pop();    
204    while(!QueueSourse.empty())
205    {
206        StructTemp=QueueSourse.front();
207        QueueSourse.pop();
208        cout<<"X"<<count+1<<"="<<StructTemp.com<<endl;
209        count++;
210    }
211    return 0;
212}